Silver halide color photographic materials, especially those for taking pictures, are required to have a high sensitivity and excellent graininess, color reproducibility and sharpness. They are further required to be free from fluctuation of the photographic properties during storage and have an excellent color image storability after processing.
Yellow couplers for forming color photographic images include the generally known acylacetanilide couplers having active methylene (methine) group(s) (T. H. James, The Theory of the Photographic Process, 4th Ed., pages 354 to 356). However, these couplers have some drawbacks because the dyes to be formed from them have a low color density and because the couplers themselves have a low dye forming speed. In particular, when the couplers are used as so-called DIR couplers, a large amount of these couplers must be used since they have a low activity. Incorporation of such a large amount of such couplers into photographic materials causes some problems because the color image fastness is lowered, the color hue becomes worse and the cost is elevated.
Malondianilide couplers which are known yellow couplers are described in, for example, U.S. Pat. Nos. 4,149,886, 4,095,984 and 4,477,563 and British Patent 1,204,680. However, the known couplers have a drawback in that the images to be formed from them have a poor image storability. In particular, the images are hardly fast to moisture and heat. In addition, with respect to spectral absorption of the azomethine dyes to be obtained from the couplers, the foot of the absorption spectrum is prolonged in the long wavelength side of yellow. Therefore, improved color reproducibility of these couplers is desired.
As a technique of providing a photographic material having a high sensitivity and excellent graininess and sharpness, incorporation of tabular silver halide grains having an aspect ratio (diameter/thickness) of 8/1 or more into a photographic material has been proposed, for example, in JP-A-58-113934. However, the proposed photographic material does not still have satisfactory color reproducibility, graininess, pressure resistance and storability. Additionally, the image storability of the processed material was still poor.